Mesenchymal stem cells (MSCs) have been isolated based on the ability of adherence to plastic surfaces. The potential of these cells to differentiate along multiple lineages is the key to identifying stem cell populations in the absence of molecular markers. Here we describe a homogenous population of MSCs from mouse bone marrow isolated using a relatively straightforward and novel approach. This method is based on the combination of frequent medium change (FMC) and treatment of the primary cultures with trypsin. Cells isolated using this method demonstrated the MSCs characteristics including their ability to differentiate into mesenchymal lineages. MSCs retained the differentiation potentials in expanded cultures up to 10 passages. Isolated MSCs were reactive to the CD44, Sca-1, and CD90 cell surface markers. MSCs were negative for the hematopoietic surface markers such as CD34, CD11b, CD45, CD31, CD106, CD117 and CD135. The data presented in this report indicated that this method can result in efficient isolation of homogenous populations of MSCs from mouse bone marrow.

Due to pluripotency of embryonic stem (ES) cells, these cells are an invaluable in vitro model that investigates the influence of different physical and chemical cues on differentiation/development pathway of specialized cells. We sought the effect of roughness and alignment, as topomorpholocial properties of scaffolds on differentiation of green fluorescent protein-expressing ES (GFP-ES) cells into three germ layers derivates simultaneously. Furthermore, the effect of Matrigel as a natural extracellular matrix in combination with poly(lactic-co-glycolic acid) (PLGA) nanofibrous scaffolds on differentiation of mouse ES cells has been investigated. The PLGA nanofibrous scaffolds with different height and distribution of roughness and alignments were fabricated. Then, the different cell differentiation fats of GFP-ES cells plated on PLGA and PLGA/Matrigel scaffolds were analyzed by gene expression profiling. The findings demonstrated that distinct ranges of roughness, height, and distribution can support/promote a specific cell differentiation fate on scaffolds. Coating of scaffolds with Matrigel has a synergistic effect in differentiation of mesoderm-derived cells and germ cells from ES cells, whereas it inhibits the derivation of endodermal cell lineages. It was concluded that the topomorpholocial cues such as roughness and alignment should be considered in addition to other scaffolds properties to design an efficient electrospun scaffold for specific tissue engineering.

A growth factor‐mediated selection method was used to obtained insulin‐secreting cells from human embryonic stem cells (hESC; Royan H1). Our resultant cells were positive for dithizone, a zinc‐chelating agent known to selectively stain pancreatic β cells and immunoreactive for antibodies against insulin, glucagon, and C‐peptide. Semi‐quantitative reverse transcription–polymerase chain reaction detected expression of proinsulin, insulin and other pancreatic β‐cell‐related genes, such as Nkx6.1, Is11, Glut2, Pax4, and prohormone convertase2 (PC2). Moreover, glucagon, somatostatin, K_ATP‐channel genes KIR6.2 and SUR1, islet amyloid polypeptide (IAPP), PC1/3, and glucokinase (GCK) were expressed in the differentiating hESC in a developmental stage‐dependent manner. Also, the addition of glucose to the culture medium triggered insulin release from differentiated cells, but transmission electron microscopy of the differentiated cells did not show typical β‐cell granules, even though secretary granules were detected. The results showed that hESC have the ability to transcribe and process insulin, but further improvements of the current method are required to generate a sufficient source of true β cells for the treatment of diabetes mellitus.